Παραπομπή APA

Ojakangas, R. W., & Darby, D. G. (1976). The earth: :Past and present. Mc Graw Hills.

Παραπομπή Chicago Style

Ojakangas, Richard W., και David G. Darby. The Earth: :Past and Present. New York: Mc Graw Hills, 1976.

Παραπομπή MLA

Ojakangas, Richard W., και David G. Darby. The Earth: :Past and Present. Mc Graw Hills, 1976.